García was born in North Philadelphia ("North Philly") to a mother from Bayamón, Puerto Rico and Ángel García originally from Naguabo, Puerto Rico, who was also a boxer.[1] It was his father who introduced him to boxing, taking him to Philadelphia's Harrowgate Boxing Club when he was ten years old, the minimum age allowed by local law for a minor to train. García Sr. has since been his primary boxing coach. Having been raised in the city with the second largest Puerto Rican community in the United States, García identified with his heritage, stating early in his career the desire to become the "next great Puerto Rican fighter".[2] Garcia admired Boxing Hall of Famer Carlos Ortíz as his favorite boxer and considered Ortíz's fight against Lenny Matthews in Philadelphia among the most memorable he had ever witnessed.

García made his professional debut on November 17, 2007, at the Borgata Hotel Casino in Atlantic City, New Jersey against Mike Denby. He opened up by throwing power shots, but it was a short right that sent Denby to the canvas. Another right put Denby down again in a neutral corner. García moved in for the knockout, and sent Denby down for the third and final time with a right-left combination. After the third knockdown, the referee waved the bout over.[4] His next fight took place on the undercard of the Floyd Mayweather, Jr.-Ricky Hatton superfight on December 8, 2007, at the MGM Grand in Las Vegas, Nevada. García defeated Jesús Villareal by second round technical knockout. On January 11, 2008, at the Morongo Casino, Resort & Spa in Cabazon, California, García defeated Marlo Córtez by second round knockout. With precise accurate punches, he disabled Cortéz, dropping him with a left hook early in the second round, forcing the referee to stop the contest.[5] On March 15, 2008, at the Mandalay Bay Resort & Casino in Las Vegas, García fought Charles Wade. He utilized his speed and quickness to get close to Wade before blasting him with a left hook to knock him out.[6]

In his fifth professional fight, García fought Guadalupe Díaz, on April 19, 2008, at the Thomas & Mack Center in Las Vegas. He hurt Díaz early in the fight with a barrage of punches. The referee was forced to stop the fight after Díaz was on wobbly legs.[7] His next fight took place on May 3, 2008, at the Home Depot Center in Carson, California against Julio Gamboa. García was in command of the fight, using his fast hands and good power to win by unanimous decision.[8] On the undercard of the Bernard Hopkins-Kelly Pavlik fight for the world middleweight championship at Boardwalk Hall in Atlantic City, García stopped Dean Nash by technical knockout after three knockdowns in the third round.

He survived a tough fight with Ashley Theophane in February 2010, coming away with a split-decision victory. García knocked out faded contender Mike Arnaoutis in four rounds later in the year. In his next contest held in April 2011, he defeated former lightweight titlist Nate Campbell. On August 15, 2011, García won the vacant NABO Jr. Welterweight belt in Los Angeles fighting on the HBO PPV undercard of Hopkins vs. Dawson, on a split decision over former champion Kendall Holt.

In his first world title contest, García faced Mexican legend and Ring Top 10 Light Welterweight, Erik Morales, for the WBC Super Lightweight World Championship in another chapter of the infamous "Puerto Rico vs. Mexico" boxing rivalry. He began the fight slowly, which Morales used to his advantage and injured his nose. As the fight progressed, García gained control, scoring a knockdown in the eleventh round before receiving a unanimous decision in his favor.[9] The scores granted by the judges were 118–111, 117–110 and 116–112.

On 14 July 2012 at Mandalay Bay in Las Vegas, Garcia met Amir Khan, who was the #3 ranked light welterweight by The Ring. The fight was a title unification bout, as Garcia's WBC title and Khan's WBA Super title were both on the line. Khan entered the fight as a heavy favorite, with betting odds at 1-7 in his favor.

The fight got off to a bad start for Garcia as Khan seemed much too fast for him. Khan won the first two rounds and was well on his way to winning the third, but with twenty-nine seconds left in the round Garcia countered a Khan combination with a left hook that caught his opponent with a left to the neck and dropped him to the canvas. Khan rose to his feet quickly but had been hurt by the punch, and referee Kenny Bayless took an extra few seconds after administering the standing eight count to make sure that Khan could continue. Garcia resumed his attack and nearly finished off Khan, who was saved when the bell rang to end the round. Eight seconds into the fourth Khan, now on unsteady legs, could not withstand a barrage of punches from Garcia, who was now taking control of the fight. Garcia kept pounding away at Khan, who lost his balance and touched the canvas with his gloves, thus forcing Bayless to administer another standing eight count as a fighter is considered down once any body part of his other than his feet touch the ring after a punch.

Khan tried desperately to rally and stay in the fight. However, with forty-eight seconds left in the round Khan was smacked senseless for a third time. This time, Khan got up quickly and appeared to have recovered from the barrage of earlier and told Bayless he was okay to continue. Bayless, after considering Khan's position, decided that the champion had taken enough punishment and stopped the fight, awarding a technical knockout victory and the WBA Super championship to Garcia.[10]

Garcia's next fight was a rematch against Ring Top 10 Light Welterweight, Erik Morales. The fight took place on October 20, 2012, in Brooklyn. Danny Garcia retained his WBC, WBA (Super) & The Ring Light Welterweight titles by knocking out Erik Morales with a thunderous left hook in the fourth round. Here is how FOX Sports described how Danny Garcia knocked out Erik Morales:

"Morales is dancing in the opening seconds, but is that because he's got a second wind or because he still doesn't know where he is? He did head to the wrong corner at the end of the last round.

This is a bad omen folks. Garcia is tapping Morales' guard with his left hand, literally telling Morales where the next shot is going to come. After four taps, Morales decides it's time to get aggressive. Bad move. Garcia blasts Morales with a left hook that launches Morales through the ropes. You can see it in Morales' eyes, he's not getting back up. KO for Garcia."

Nevertheless, Garcia stood firm and fought a mature fight. Matthysse won several of the early rounds, putting heavy pressure on the champion by utilizing speed and punching power. In the middle rounds, Matthysse sustained an injury to his right eye from a Garcia flinch, to which Garcia targeted the eye throughout the remainder of the fight, subsequently taking the lead on the scorecards and closing the challengers eye. In the eleventh round Matthysse landed a punch that knocked out Garcia's mouthpiece, but Garcia turned the tables and knocked Matthysse down in the 11th round with a four-punch combination. Garcia was docked a point in the final round for low blows, but the last round was very competitive with both champion and challenger trading big shots. Garcia took the unanimous decision (115-111, 114-112 and 114-112), giving Matthysse his first decisive loss. This fight also clarified that Garcia's chin is capable of taking big shots, as it was widely touted before the fight that Garcia would not be able to absorb the huge punching power that Matthysse is famous for.[12]

For beating Judah and Matthysse, Garcia was named 2013 Boxer of the Year by Stiff Jab.[13]

On January 14, 2015, NBC announced a partnership with Premier Boxing Champions to air premium fights on network television. It was announced that Danny Garcia vs. Lamont Peterson would fight April 11, 2015 on NBC primetime.[15] The fight will be at the Barclays Center in Brooklyn, NY.[16]